let currentId = 1
let allIdList = []

export default {
    create() {
        let id = ++currentId
        allIdList.unshift(id)
        return id
    },
    remove(id) {
        allIdList = allIdList.filter(a => a != id)
    },
    isTop(id) {
        return allIdList[0] == id
    },
}